The earliest hematologic manifestation of megaloblastic anemia is

Microcytic anemiaMacrocytic anemiaSideroblastic anemiaIron deficiency anemiaThalassemiaAnemia of chronic disease Liver disease Hypothyroidism Folic acid & vitamin B12 deficiency Cytotoxic drugs Megaloblastic anemiaTriad - Oval macrocyte , Howel Jolly bodies , Hypersegmented neutrophilsBone marrow - hypercellular bone marrow with megaloblast along with the presence of abnormal granulocytic precursors ( giant metamyelocyte & band forms ) and large megakaryocytes with bizarre multilobate nuclei Peripheral smear - pancytopenia with presence of macrocyte (MCV>100 fl) lacking central pallor ; large hypersegmented neutrophils ( >5 lobes )(Refer: Robbins & Cotran's - Pathologic Basis of Disease, SAE, 1st edition, Vol I-pg no: 643-648)